1. Field of the Invention:
The invention relates to electrical terminals for elongated elements, and in particular, to an electrical supporting terminal for a high temperature element, such as a molybdenum disilicide resistance element used as an igniter or sensor for a flame.
2. Description of the Prior Art:
Prior art terminals for igniter elements including molybdenum disilicide elements, as exemplified in U.S. Pat. Nos. 1,496,596, 2,384,797, 3,522,574, 3,562,590, 3,569,787 and 3,662,222 have been made by crimping, brazing, soldering, welding, bonding or otherwise joining metal terminal members or sleeves to the elements. Generally, the prior art terminals for molybdenum disilicide elements have been of limited suitability due to failure at or near the junction between the element and the terminal members during the joining process, handling shocks or repeated use; some of the failures result from rapid deteriation in strength and conductivity of materials used in making the terminals or junctions. Welding the elements to heat-resistant metal terminals avoids failures due to rapid deteriation in strength and conductivity of the terminals; however, welding of molybdenum disilicide elements to commonly used heat-resistant metals has previously not been entirely satisfactory because the elements tend to break at or near the welded junction during or after the welding process. Provision of separate mechanical support for molybdenum disilicide elements eliminates some of the failures during subsequent handling; however, such provision has not been completely successful, and also failures still occur prior to providing the mechanical support.
Additionally, a number of techniques have been developed in the prior art to connect dissimilar metal members, such as conductors, tubes, etc. used in relatively low temperature applications, as exemplified by U.S. Pat. Nos. 3,656,092, 3,244,798 and 2,914,641. Generally, such techniques are inapplicable or unsuitable for high temperature electrical resistance elements, such as molybdenum disilicide elements, in that the materials employed are substantially deteriorated in strength or conductivity by high temperatures, air and fuel.